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   comp.arch      Apparently more than just beeps & boops      131,241 messages   

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   Message 130,497 of 131,241   
   Dan Cross to johnl@taugh.com   
   Re: instruction ordering, was Memory ord   
   12 Dec 25 13:05:43   
   
   From: cross@spitfire.i.gajendra.net   
      
   In article <10hfrsl$145v$1@gal.iecc.com>, John Levine   wrote:   
   >According to Thomas Koenig  :   
   >>MitchAlsup  schrieb:   
   >>   
   >>> Heck, there are assemblers that rearrange code like this too much--   
   >>> until they can be taught not to.   
   >>   
   >>Any example?  This would definitely go against what I would consider   
   >>to be reasonable for an assembler.  gdb certainly does not do so.   
   >   
   >On machines with delayed branches I've seen assemblers that move   
   >instructions into the delay slot.  Can't think of any others off hand.   
      
   I've seen things like this, as well, particularly on machines   
   with multiple delay slots, where this detail was hidden from the   
   programmer.  Or at least I have a vague memory of this; perhaps   
   I'm hallucinating.   
      
   More dangerous are linkers that do LTO and decide to elide code   
   that, no, really, I actually need for reasons that are not   
   apparent to the toolchain.   
      
   	- Dan C.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

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